The overall aim of this research is to develop a rapid, quantitative microplate-based whole animal zebrafish caspase assay which can be used to identify apoptosis inducers and inhibitors. We will validate the assay with known inhibitors and inducers of apoptosis and compare our findings with results observed in cell and mammalian assays. Since the early-mid 1990's, numerous, diverse assays for measuring apoptosis have been developed paralleling the increased interest in apoptosis research. Apoptosis is an evolutionarily conserved mechanism, and homologs of the endoproteases responsible for cell death, caspases, have been identified in several metazoans, including zebrafish. Because of their genetic and physiological similarity to humans, zebrafish show promise as an efficient animal model for drug screening. Zebrafish is exceptionally well suited for studies that combine cellular, molecular, and genetic approaches. Because zebrafish develop rapidly, drug effects can be observed within days instead of weeks or months. Zebrafish embryos are completely transparent, facilitating observation and analysis. PUBLIC HEALTH RELEVANCE: In the current proposal, we will develop a quantitative caspase assay in whole zebrafish. By providing a rapid assay for prescreening drug candidates prior to performing expensive mammalian testing, the proposed zebrafish assay will facilitate drug development for certain forms of cancer, was well as other diseases including: autoimmune diseases, tissue damage, inflammatory disease, AIDS, and neurodegenerative diseases.